DOI: 10.1002/ejoc.70875 ISSN: 1434-193X

Synthesis of α‐ C ‐Glycoside Conjugates Promoted by 4CzIPN‐Based Porous Organic Polymers Through Giese‐Like Reaction of Glycosyl Bromides in Batch and Continuous Flow

Francesco Riina, Laura Manfrin, Lorenzo Poletti, Daniele Ragno, Carmela De Risi, Alessandro Massi, Graziano Di Carmine

A visible‐light‐mediated strategy for the synthesis of α‐ C ‐glycoside conjugates using a 4CzIPN‐based porous organic polymer 4CzIPN‐POP as a heterogeneous photocatalyst is reported. The method exploits the photochemical generation of anomeric radicals from glycosyl bromides, followed by Giese‐like addition to electron‐poor olefins, enabling the formation of C ‐glycosidic linkages under mild conditions. After preliminary identification of 4CzIPN as the most effective molecular photocatalyst, its heterogenized porous analogue was prepared and evaluated in batch, where it promoted the formation of glycoconjugates with amino acid‐, bisphosphonate‐, and acrylate‐derived acceptors. Although heterogeneous conditions generally resulted in diminished yields relative to the homogeneous counterpart, the catalyst proved compatible with a range of mono‐ and disaccharide substrates while maintaining high stereoselectivity in most cases. To overcome the intrinsic limitations of light penetration in suspension, the heterogeneous system was translated to a packed‐coil continuous flow photoreactor, leading to improved efficiency and enabling scale up of reaction. These results demonstrate that 4CzIPN‐POP is a viable heterogeneous platform for anomeric radical generation and C ‐glycoside synthesis and highlight continuous flow as an effective technological solution for enhancing the performance of polymer‐supported photocatalytic processes.